Forming through holes through exposed dielectric material of component carrier

ABSTRACT

A method of manufacturing a component carrier is provided. The method includes forming a through hole between a first main surface and a second main surface of an electrically insulating layer structure by removing material from at least one of the main surfaces of the electrically insulating layer structure, in particular by irradiating at least one of the main surfaces of the electrically insulating layer structure with at least one laser shot, wherein the at least one main surface from which material is removed, in particular which is to be irradiated, is not covered by an electrically conductive layer structure at least in a surface region in which the through hole is to be formed, and subsequently at least partially filling the through hole and at least partially covering the main surfaces of the electrically insulating layer structure by an electrically conductive filling medium.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of and claims the benefit ofthe filing date of U.S. Non-Provisional patent application Ser. No.16/262,982, filed Jan. 31, 2019, the entire disclosure of which ishereby incorporated herein by reference.

TECHNICAL FIELD

The invention relates to component carriers and methods of manufacturinga component carrier.

TECHNOLOGICAL BACKGROUND

In the context of growing product functionalities of component carriersequipped with one or more electronic components and increasingminiaturization of such components as well as a rising number ofcomponents to be mounted on the component carriers such as printedcircuit boards, increasingly more powerful array-like components orpackages having several components are being employed, which have aplurality of contacts or connections, with ever smaller spacing betweenthese contacts. Removal of heat generated by such components and thecomponent carrier itself during operation becomes an increasing issue.At the same time, component carriers shall be mechanically robust andelectrically reliable so as to be operable even under harsh conditions.All these requirements go hand in hand with a continued miniaturizationof component carriers and their constituents.

In particular, it may be advantageous to efficiently contactelectrically conductive layer structures and/or components mounted onand/or embedded in a component carrier with proper quality. Formation ofmechanical vias and laser vias, which may be copper filled, may beadvantageous for this and other purposes. However, when forming throughholes by laser drilling in a core comprising a dielectric central layer,with two copper foils on both opposing main surfaces thereof, anundesired lateral overhang of the laser patterned copper foils beyondthe dielectric central layer with its through hole may be obtained. Theterm “overhang” may denote a partial length of the electricallyconductive layer structure directly adjacent to a respective one of thewindows extending through the electrically conductive layer structuresover which length the respective portion of the electrically conductivelayer structure hangs freely in a cantilever fashion spaced with regardto the electrically insulating layer structure and is not supported frombelow by material of the electrically insulating layer structure alongthe extension of the overhang. Such an overhang may result in cracks orvoids in the through hole when filled with copper. As a result, thecomponent carrier may have a limited electric reliability.

SUMMARY

There may be a need to manufacture a component carrier with properelectric reliability.

According to an exemplary embodiment of the invention, a method ofmanufacturing a component carrier is provided, wherein the methodcomprises forming a through hole (in particular a laser through hole)between a first main surface and a second main surface of anelectrically insulating layer structure by removing material from atleast the first main surface of the electrically insulating layerstructure (in particular by irradiating at least the first main surfaceof the electrically insulating layer structure with at least one lasershot), wherein the first main surface from which material is removed (inparticular which is to be irradiated) is not covered by an electricallyconductive layer structure at least in a surface region in which thethrough hole is to be formed, and subsequently at least partiallycovering sidewalls delimiting the through hole and at least partiallycovering the first main surface of the electrically insulating layerstructure by an electrically conductive medium to form an integralelectrically conductive structure. The integral electrically conductivestructure is formed by at least two galvanic plating processes to haveat least an electrically conductive bridge structure having asubstantially horizontal portion connecting the opposing sidewalls ofthe through hole and a first electrically conductive bulk structure onthe electrically conductive bridge structure, wherein a distance betweena point on the sidewall, at which a width of the through hole isminimum, and a lowermost point of the first electrically conductive bulkstructure is at least 20 μm.

In an alternative embodiment, a component carrier is provided. Thecomponent carrier includes an electrically insulating layer structurehaving a first main surface and a second main surface; a through holeextending through the electrically insulating layer structure betweenthe first main surface and the second main surface; an integralelectrically conductive structure covering sidewalls of the throughhole, extending up to one or both of the main surfaces and covering atleast part of at least one of the main surfaces of the electricallyinsulating layer structure; wherein the integral electrically conductivestructure has at least two galvanically plated layers which form anelectrically conductive bridge structure having a substantiallyhorizontal portion connecting the opposing sidewalls of the through holeand a first electrically conductive bulk structure on the electricallyconductive bridge structure, wherein a distance between a point on thesidewall, at which a width of the through hole is minimum, and alowermost point of the first electrically conductive bulk structure isat least 20 μm.

Overview of Embodiments

The method of manufacturing a component carrier can comprise at leastone of the following features: no electrically conductive layerstructure, in particular no copper foil, is arranged between theintegral electrically conductive structure and the first main surface;the integral electrically conductive structure is arranged on a seedlayer; a total thickness of at least two galvanically plated metallayers of the integral electrically conductive structure issubstantially homogenous in at least a part of the through hole and inat least a part of the first main surface; wherein a portion of agalvanically plated metal layer in the through hole, which includes thebridge structure, has a thickness which increases in a direction fromthe first main surface towards the second main surface to a valuesmaller than a narrowest horizontal diameter of the through hole so thatthe substantially horizontal portion has a concave first demarcationsurface.

According to another exemplary embodiment of the invention, the methodcomprises providing the electrically insulating layer structure with athickness of less than 110 μm, wherein the through hole is formed (inparticular with one or more laser shots only from one main surface ofthe electrically insulating layer structure but not from the other mainsurface, or with one or more laser shots from the first main surface andone or more further laser shots from the second main surface; possibleis in particular the formation of the laser through hole with only onelaser shot only from one main surface only, which may also result in afirst partial hole and a second partial hole having different values ofroughness) with a first partial hole extending from the first mainsurface into the electrically insulating layer structure, with a secondpartial hole extending from the second main surface into theelectrically insulating layer structure, and with a lateral offsetbetween a center axis of the first partial hole and a center axis of thesecond partial hole being less than 3 μm (in particular less than 1 μm).

According to another exemplary embodiment of the invention, n the methodcomprises forming at least one electrically conductive track partiallycovering at least one of the main surfaces of the electricallyinsulating layer structure and comprising a second number of multiplestacked structures, wherein a difference between the first number andthe second number is zero or one, wherein in particular the first numberis three or four and/or the second number is three.

According to another exemplary embodiment of the invention, a componentcarrier is provided which comprises an electrically insulating layerstructure having a first main surface and a second main surface, athrough hole extending through the electrically insulating layerstructure between the first main surface and the second main surface,and an integral electrically conductive structure covering sidewalls ofthe through hole, extending up to (and for instance continuously along)one or both of the main surfaces and covering at least part of at leastone of the main surfaces of the electrically insulating layer structure.

The integral electrically conductive structure comprises at least twogalvanically plated layers which form an electrically conductive bridgestructure having a substantially horizontal portion connecting theopposing sidewalls of the through hole and a first electricallyconductive bulk structure on the electrically conductive bridgestructure, wherein a distance between a point on the sidewall, at whicha width of the through hole is minimum, and a lowermost point of thefirst electrically conductive bulk structure is at least 20 μm.

According to another exemplary embodiment of the invention, theelectrically insulating layer structure has a thickness of less than 110μm and the through hole may be optionally at least partially filled withan electrically conductive filling medium, as described herein, whereinthe through hole has a first partial hole extending from the first mainsurface into the electrically insulating layer structure, and a secondpartial hole extending from the second main surface into theelectrically insulating layer structure, wherein a lateral offsetbetween a center axis of the first partial hole and a center axis of thesecond partial hole is less than 3 μm, in particular is less than 1 μm.

According to another exemplary embodiment of the invention, thecomponent carrier is provided which comprises the electricallyconductive filling medium (which may have the properties as describedherein) at least partially filling the through hole and comprising afirst number of multiple stacked structures (such as a plating layer, abridge structure, a first bulk structure and a second bulk structure),and at least one electrically conductive track partially covering atleast one of the main surfaces of the electrically insulating layerstructure and comprising a second number of multiple stacked structures(such as a plating layer, a bridge structure, and a first bulk structureor a second bulk structure), wherein a difference between the firstnumber and the second number is zero or one (wherein the first numbermay in particular be three or four, and the second number may inparticular be three).

A total thickness of at least two galvanically plated metal layers ofthe integral electrically conductive structure can substantially behomogenous in at least a part of the through hole and in at least a partof the at least one main surface.

A portion of a galvanically plated metal layer in the through hole,which includes the bridge structure, can have a thickness whichincreases in a direction from the first main surface towards the secondmain surface to a value smaller than a narrowest horizontal diameter ofthe through hole so that the substantially horizontal portion has aconcave first demarcation surface.

In the context of the present application, the term “component carrier”may particularly denote any support structure which is capable ofaccommodating one or more components thereon and/or therein forproviding mechanical support and/or electrical connectivity. In otherwords, a component carrier may be configured as a mechanical and/orelectronic carrier for components. In particular, a component carriermay be one of a printed circuit board, an organic interposer, and an IC(integrated circuit) substrate. A component carrier may also be a hybridboard combining different ones of the above-mentioned types of componentcarriers.

In the context of the present application, the term “layer structure”may particularly denote a continuous layer, a patterned layer or aplurality of non-consecutive islands within a common plane.

In the context of the present application, the term “through hole” mayparticularly denote a hole extending vertically through the entireelectrically insulating layer structure, and which may be formed inparticular by laser processing (wherein formation of the through hole bya plasma process or the like is possible as well). Thus, the throughhole may be a laser through hole in one embodiment. More specifically,such a through hole may be a through hole having tapering portions ontwo opposing main surfaces of the electrically insulating layerstructure, for instance as a result from the energy impact of laserbeams which are irradiated onto one or both of the two opposing mainsurfaces of the electrically insulating layer structure.

In the context of the present application, the term “integralelectrically conductive structure” may particularly denote a continuousstructure of electrically conductive material (in particular copper,more particularly plated copper) having homogeneous material propertiesand being distinguishable (in particular when inspecting a cross-sectionof the component carrier) from other constituents of the componentcarrier, in particular from adjacent electrically conductive material. Askilled person is aware of the fact that a plated integral electricallyconductive structure lining at least part of side-walls of the throughhole and at least part of main surfaces of an electrically insulatinglayer structure can be visually distinguished or separated from otherelectrically conductive material, such as another plating structure,another structure formed by electroless deposition, a metal foil, etc.Thus, the entire electrically conductive material of the integralelectrically conductive structure may relate to and may belong to thewhole integral electrically conductive structure, in particular withoutintrinsic interfaces or discontinuities or material transitions.

According to an exemplary embodiment of the invention, a manufacturingmethod for manufacturing a component carrier with through hole beingpartly or entirely filled with electrically conductive material isprovided, wherein the electric reliability of the filled through hole ishighly advantageous. In such an embodiment, a dielectric layer structure(such as a core layer, i.e. fully cured dielectric material withoutcopper) comprising one or multiple through holes is provided which doesnot suffer from overhang and related phenomena as a result of lackingelectrically conductive layer structures covering the dielectric layerstructure at least during through hole drilling and/or at least in adrilling region. According to such a concept, a dielectric body beingfree of electrically conductive material on one or even both opposingmain surfaces may be directly irradiated with one or more laser beams(or may be treated in another appropriate way) for forming a throughhole. Thus, an exposed electrically insulating layer structure may bedirectly made subject of laser drilling or another material removalprocedure, rather than covering it with electrically conductive materialprior to laser drilling or the other material removal procedure throughthe covering electrically conductive material. As a result of theomission of electrically conductive material on a surface of anelectrically insulating layer structure during laser drilling or thelike, there is no risk of the formation of undesired overhang or bottleholes. In particular what concerns thin core layers, such amanufacturing method may also largely prevent a front side to back sideoffset. Thus, a simply manufacturable and highly reliably componentcarrier with a homogeneous copper layer structure may be obtained.Further advantageously, such a copper filled via may also be not proneto mechanical failure even when significant temperature changes/thermalcycles impact the component carrier. Thus, a high electricalreliability, a high mechanical reliability and a high thermalreliability of the component carrier may be advantageously obtained bythe mentioned concept of forming through holes in a purely dielectriclayer structure.

According to another exemplary aspect, it may be advantageously possibleto (in particular partially or entirely simultaneously, or sequentially)form an electrically conductive filling medium in the through hole andone or more electrically conductive tracks on one or both of theopposing main surfaces of the electrically insulating layer structurewith numbers of sublayers differing by one. It may also be possible toform at least part of the tracks on an electrically conductive layerstructure (such as a copper foil) which may be present at leasttemporarily and/or at least partially on the electrically insulatinglayer structure. Alternatively, the electrically conductive fillingmedium in the through hole and the one or more tracks may have the samenumber of sublayers (for instance when applying a semi-additiveprocessing and patterning procedure). This is a very efficient mechanismof simultaneously plating a through hole and forming an electricallyconductive wiring on the main surfaces of the dielectric layer.

In the following, further exemplary embodiments of the componentcarriers and the methods will be explained.

In particular, the method may comprise forming the through hole in theelectrically insulating layer structure while one or both of the mainsurfaces of the electrically insulating layer structure is or are notcovered by an electrically conductive layer structure. In such anembodiment, the laser beam forming the through hole may directly impactand may directly remove material from an exposed dielectric surface areaof the electrically insulating layer structure without previouslypropagating through electrically conductive material. Thus, the throughhole may be drilled directly through the electrically insulating layerstructure alone. Since this procedure involves no lateral overhang of anelectrically conductive layer structure beyond the electricallyinsulating layer structure at all, a high reliability can be obtained insuch an embodiment.

In an embodiment, forming the through hole comprises irradiating thefirst main surface, being not covered by an electrically conductivelayer structure, with a first laser shot (which may be exactly one firstlaser shot or a plurality of first laser shots) and irradiating thesecond main surface, being not covered by an electrically conductivelayer structure, with a second laser shot, in particular exactly onesecond laser shot. Thus, the electrically insulating layer structure maybe exposed at the point of time where the respective laser shot isirradiated onto the respective main surface of the electricallyinsulating layer structure. No electrically conductive layer structure,and in particular no metal foil, covers the electrically insulatinglayer structure at this point of time. As a result, there is no issuewith overhang which can conventionally result in the formation ofcracks. Furthermore, the mentioned approach is very simple.

In an embodiment, forming the through hole comprises irradiating thefirst main surface, being not covered by an electrically conductivelayer structure, with a first laser shot (which may be exactly one firstlaser shot or a plurality of first laser shots) and irradiating thesecond main surface, being not covered by an electrically conductivelayer structure, with (in particular at least or exactly) two secondlaser shots. A relatively homogeneous geometry of the through holeextending through the electrically insulating layer structure may beobtained by laser drilling from both opposing main surfaces of theuncovered dielectric surface area of the electrically insulating layerstructure.

In another embodiment, forming the through hole comprises irradiatingthe electrically insulating layer structure only from the first mainsurface, not from the second main surface. In particular, the first mainsurface may be laser drilled with one or multiple laser shots. Dependingon the parameters used for laser drilling only from one side of theelectrically insulating layer structure, the laser through hole may havea straight geometry or may have a frustoconical geometry. This is a verysimple and fast approach of forming laser through holes. In a panel oran array comprising a set of component carriers during manufacture, itmay be necessary to form more than 100,000 or even more than 1 millionlaser generated through holes per panel or array.

In an embodiment, the at least one main surface to be irradiated isentirely not covered at all by an electrically conductive layerstructure during the irradiating. For instance, a purely dielectriclayer structure without any surface metal may be irradiated with thelaser beam(s).

In another embodiment, the at least one main surface to be irradiatedis, during the irradiating, covered only partially by an electricallyconductive layer structure in a surface region of the at least one mainsurface which surface region is not to be irradiated by the at least onelaser shot. In other words, a main surface to be irradiated with a laserbeam may be at least partially covered with electrically conductivematerial, wherein however a target portion of the respective mainsurface, which target surface is to be irradiated with a laser beam, isfree of electrically conductive material already before switching on thelaser beam for irradiation of this target surface. For instance, thesurface region being free of electrically conductive material may belarger than an exterior area of the through hole at the correspondingmain surface of the electrically insulating layer structure.

In particular, the method may comprise, before the irradiating, formingan electrically conductive layer structure on the at least one mainsurface to be irradiated, and subsequently but still before theirradiating starts, removing part of the electrically conductive layerstructure at least in a surface portion of the at least one main surfacewhich is to be irradiated by the at least one laser shot. For instance,electrically conductive material covering the main surface to beirradiated may be partially etched away, may be removed mechanically,etc., before switching on the laser beam for irradiation of this targetsurface.

Advantageously, formation of through holes in copper-less surfaces mayreduce mechanical tensions or stress (and in particular warpage) at thepanel. Without wishing to be bound to a specific theory, it is presentlybelieved that such mechanical tensions or stress and in particularwarpage may be unintentionally created by a punctual heating of a copperlayer adjacent to a laser bore.

In an embodiment, forming the through hole comprises directlyirradiating at least one of the exposed main surfaces of theelectrically insulating layer structure with the at least one lasershot. In the context of the present application, the term “directlyirradiating” may particularly denote that the directly irradiatedelectrically insulating layer structure is exposed at the time ofirradiation without being covered with metallic material. This avoidsissues such as overhang and improves the electric reliability of theobtained component carrier.

In an embodiment, the method comprises forming at least part of theelectrically conductive filling medium by forming a plating layer, inparticular having a substantially homogeneous thickness, as an integralstructure covering at least part of sidewalls of the through hole and atleast partially covering the main surfaces. Formation of this platinglayer may follow the optional previous formation of a seed layer. Duringthe manufacturing process, it may be possible to firstly cover thesidewalls of the through hole with a thin seed layer of electricallyconductive material (preferably copper), for instance by electrolessdeposition. Subsequently, the plating structure may be formed by aplating procedure, for instance by galvanic plating. During such aplating procedure, the sidewalls may be covered with a thicker layer ofelectrically conductive material. Thus, the plating layer may becomposed of a seed layer being covered with further plated material.After having formed an optional thin seed layer covering the sidewalls(for instance having a thickness in the range between 0.1 μm and 5 μm,for instance 1 μm) of electrically conductive material such as copper, asubstantial amount of electrically conductive material (preferablycopper) may be formed on this seed layer preferably by plating orgalvanic deposition (for instance with a thickness in the range between6 μm and 30 μm). It is possible that the seed layer is a single layerand/or that several cumulative seed layers are provided. When multipleseed layers are provided, they may comprise an organic (for instancepolymer) layer, a palladium layer, a titanium layer and/or a copperlayer. Also other adhesion promoting materials may be used, preferablycovered by copper. In an embodiment, it is also possible to form theseed layer or part thereof by PVD (physical vapor deposition) techniqueslike sputtering.

In an embodiment, the plating layer may be an annular plating layer. Inthe context of the present application, the term “annular plating layer”may particularly denote a plating layer with the shape of an annulus ora ring. An annular plating layer may therefore be circumferentiallyclosed and may have a through hole extending vertically therethrough.The annular plating layer may be formed partially on the sidewalls andpartially on the top and bottom main surfaces of the electricallyinsulating layer structure, either directly on the electricallyinsulating layer structure or separated by a seed layer or the like. Avertically continuous portion of the laser through hole may remain openafter having formed the annular plating layer. It has turned out that byplating sidewalls of the electrically insulating layer structuredelimiting the through hole and at least part of top and bottom walls ofthe electrically insulating layer structure by a separate annularplating layer, crack formation can be significantly suppressed andelectric reliability of the electrically conductive filling of the laserthrough hole may be improved.

In an embodiment, the method comprises forming, in particular byplating, a further part of the electrically conductive filling medium byforming an electrically conductive bridge structure on the plating layerand connecting opposing sidewalls of the electrically insulating layerstructure delimiting the through hole. Correspondingly, the componentcarrier may comprise an electrically conductive bridge structure, inparticular being substantially H-shaped, on the plating layer andconnecting opposing sidewalls of the electrically insulating layerstructure delimiting the through hole. In the context of the presentapplication, the term “bridge structure” may particularly denote anelectrically conductive structure extending substantially horizontallybetween opposing sidewalls of the electrically insulating layerstructure and delimiting the through hole, in particular at or close toa narrowest portion of the through hole. For instance, such a bridgestructure can be formed by plating following through hole formation andfollowing formation of the above-mentioned plating layer. After such aplating procedure, the previously formed through hole may be onlypartially filled with electrically conductive material constituting thebridge structure, so that the bridge structure is delimited in an upwarddirection by a first demarcation surface and at a lower side by a seconddemarcation surface. Both the first demarcation surface and the seconddemarcation surface may have a concave shape. The above procedure offorming the plating layer may thus be followed by the formation of aconnection between the side-walls with plating material in form of thebridge structure, in many cases at or close to a narrowest portion ofthe through hole. Thus, a substantially H-shaped bridge structure with ahorizontal bridge part and slanted legs on the plating layer may beobtained.

In an embodiment, the component carrier comprises a first electricallyconductive bulk structure filling at least part of a volume above thefirst demarcation surface, i.e. filling at least part of a dimple abovethe first demarcation surface. In an embodiment, the component carriercomprises a second electrically conductive bulk structure filling atleast part of a volume below the second demarcation surface, i.e.filling at least part of a dimple below the second demarcation surface.Correspondingly, the method may comprise forming a first electricallyconductive bulk structure filling at least part of a volume between thefirst demarcation surface and the first main surface and/or a secondelectrically conductive bulk structure filling at least part of a volumebetween the second demarcation surface and the second main surface.After having completed a plating procedure of forming the bridgestructure, remaining empty spaces within the through hole above thefirst demarcation surface and/or below the second demarcation surfacemay be filled partially or entirely with further electrically conductivematerial such as copper. This filling is denoted as first and secondelectrically conductive bulk structure. Preferably, such electricallyconductive bulk structures may be formed in plating procedures beingseparate from a plating procedure of forming the bridge structure. Asknown by those skilled in the art of component carrier manufacture, atransition between the bridge structure and the bulk structures can beseen in a cross-sectional view of a manufactured component carrier.Thus, the bridge structure on the one hand and the bulk structures onthe other hand can be visually separated in a cross-sectional view ofthe component carrier.

In an embodiment, at least one of the first electrically conductive bulkstructure and the second electrically conductive bulk structure is aplating structure. Correspondingly, the method may comprise forming atleast one of the group consisting of the first electrically conductivebulk structure and the second electrically conductive bulk structure bya further plating procedure following at least one previous platingprocedure of forming the bridge structure.

In an embodiment, the method comprises forming a bonding layer, inparticular having a substantially homogeneous thickness, between atleast part of the sidewalls and at least part of the main surfaces, onthe one hand, and the plating layer on the other hand. Correspondingly,the component carrier may comprise at least one bonding layer, inparticular having a substantially homogeneous thickness, between atleast part of the sidewalls and at least part of the main surfaces, onthe one hand, and the integral electrically conductive structure on theother hand. Such a bonding layer may improve adhesion between theelectrically insulating layer structure and the plating layer and mayimprove the mechanical reliability of the component carrier.

In an embodiment, forming the through hole, in particular by laser shotsirradiated onto the electrically insulating layer structure from bothopposing main surfaces, is carried out with a uniform laser energy. Ithas turned out that a substantially constant laser energy or powerduring front side drilling and back side drilling improves thehomogeneity of the geometry of the through hole and has a positiveimpact on the electric reliability of the component carrier.

In an embodiment, the method comprises forming at least one electricallyconductive track comprising a stack of multiple plated structures on theelectrically insulating layer structure (at least partially)simultaneously with the formation of the electrically conductive fillingmedium. For instance, the stack may be formed at least partially bysemi-additive processing. Correspondingly, the plating layer, the bridgestructure and the at least one bulk structure may be patterned so as toform at least one laterally delimited further layer stack on at leastone of the first main surface and the second main surface. This may beaccomplished by forming at least one resist before and/or between and/orafter forming different constituents of the electrically conductivefilling medium, if desired combined with corresponding patterning oretching procedures. As a consequence, the formation of electricallyconductive tracks and plating of one or more laser through holes may becarried out simultaneously. This keeps the effort of manufacturingcomponent carriers small and reduces waste. By depositing and patterninga resist on surfaces of the electrically insulating layer structureand/or on the electrically conductive filling medium, the geometry ofthe tracks may be properly defined.

In an embodiment, the at least one laterally delimited further layerstack and/or a portion (which may be denoted as a protruding stack) ofthe plating layer, the bridge structure and the at least one bulkstructure extending vertically beyond the through hole have sidewallshaving an angle with a respective one of the first main surface or thesecond main surface in a range between 85° and 95°, more particularly ina range between 89° and 91°. Preferably, the angle may be a right angle,i.e. an angle of 90°. Such an angular characteristics is a fingerprintof semi-additive processing. In contrast to this, formation of thementioned stacks by etching may result in stronger slanted sidewalls.

In an embodiment, no electrically conductive layer structure (and inparticular no copper foil) is arranged between the integral electricallyconductive structure and the main surfaces. This structural feature is afinger-print of the formation of the through hole without coverage ofthe main surfaces with electrically conductive material.

In an embodiment, the integral electrically conductive structurecontinuously lines the sidewalls and at least part of the main surfaces.In particular, also an angled transition between the sidewalls and themain surfaces may be continuously (in particular fully circumferentiallyat both opposing main surfaces) covered with the integral electricallyconductive structure. The integral electrically conductive structure mayconstitute the plating layer and may be formed of a continuouselectrically conductive material, such as copper. The integralelectrically conductive structure may have a substantially homogeneousthickness. It may cover at least part of sidewalls of the through holeand may at least partially cover the main surfaces.

In an embodiment, a minimum vertical thickness of the bridge structureis at least 20 μm, in particular at least 25 μm. Experiments have shownthat when the smallest vertical thickness of the bridge structure overthe entire width thereof is at least 20 μm or preferably at least 25 μm,reliability can be further improved.

It may also be advantageous to keep the minimum thickness of the bridgestructure smaller than 40 μm. It has also been surprisingly found thatwhen the vertical thickness of the bridge structure becomes too large,dimples or concave surfaces delimiting the bridge structure as an upperdemarcation surface and a lower demarcation surface may becomeexcessively shallow. This may cause issues when subsequently filling oneor both dimples with electrically conductive material (such as copper)by plating, since it may have the tendency to cause an undesired shapeof the copper filled laser via. Therefore, it may be preferred that alsoan upper limit of the narrowest vertical thickness of the bridgestructure of not more than 40 μm is respected.

In an embodiment, a roughness Rz of at least part of the sidewalls in afirst tapering portion (which may extend from the first main surface) ofthe through hole is different from a roughness Rz of at least part ofthe side-walls in a second tapering portion (which may extend from thesecond main surface) of the through hole. Rz can be determined when areference length is sampled from a roughness curve in a direction of amean line, and may denote the distance between the top profile peak lineand the bottom profile valley line on this sampled portion as measuredin the longitudinal direction of the roughness curve. In particular, theroughness Rz of at least part of the sidewalls in the first taperingportion may be smaller than the roughness Rz of at least part of thesidewalls in the second tapering portion, and a vertical extension ofthe first tapering portion may be larger than a vertical extension ofthe second tapering portion. A smoother larger surface area of the firsttapering portion may thus be advantageously combined with a roughersmaller surface area of the second tapering portion to ensurecontinuously a proper adhesion of electrically conductive filling mediumon the sidewalls of the electrically insulating layer structuredelimiting the through hole.

In an embodiment, a thickness of the electrically insulating layerstructure is not more than 110 μm, in particular not more than 60 μm. Inparticular with relatively thin electrically insulating layerstructures, i.e. having a thickness of less than 180 μm or even 110 μmor less, reliability concerning the electrically conductive filling ofthrough holes becomes more and more an issue. When, however, the designrules mentioned herein are expected, it has turned out that even forsuch thin core layers, a proper reliability of a component carrier maybe obtained.

In an embodiment, the electrically insulating layer structure is apre-preg layer, in particular a fully cured prepreg layer consisting ofdielectric material. Such a prepreg layer may be substantially fullycured, i.e. may comprise resin which is substantially no more able tocross-link but is already highly or completely cross-linked. C-stageresin may or may not be 100% crosslinked polymer chains, but may atleast have a network of highly crosslinked polymer chains, so that thefinal product cannot be thermally reformed and is insoluble. As aconsequence, such a material will not re-melt or become flowable againduring a subsequent lamination procedure in which one or moreelectrically conductive layer structures and/or electrically insulatinglayer structures may be laminated on the top surface and/or the bottomsurface of the prepreg layer with copper filled through hole(s) duringbuild-up. For instance, such a prepreg layer may comprise resinincluding reinforcing particles such as glass fibres or glass spheres.

In an embodiment, at least a part of the through hole is substantiallyX-shaped. In particular, the through hole may have a first taperingportion extending from the first main surface and a second taperingportion extending from the second main surface. A through hole havingsuch a shape may be formed by carrying out a first laser drilling fromthe first main surface with only one laser shot and carrying out asecond laser drilling from the second main surface with only one furtherlaser shot. Thus, a substantial X-shape may be the fingerprint of amanufacturing procedure of forming the through hole using a single lasershot from the front side and a single laser shot from the back side.

In another embodiment, at least a part of the through hole has a central(for instance substantially cylindrical) section between two opposingtapering sections. A through hole having such a shape may be formed bycarrying out a first laser drilling from the first main surface with(for instance only) one laser shot and carrying out a second laserdrilling from the second main surface with (in particular exactly) twolaser shots. A correspondingly formed through hole may comprise acentral connection portion connecting the first tapering portion withthe second tapering portion. Thus, the shape of the through hole mayhave a for instance straight or substantially straight centralconnection portion between two opposing tapering portions at the upperand lower end of the through hole. The horizontal portion of the bridgestructure may then be formed at least partially in this centralconnection portion. Such a geometry may be obtained by combining asingle laser shot from the first upper main surface with two subsequentlaser shots from the second main surface.

In yet another embodiment, the laser through hole may also have afrustoconical shape or even a substantially straight shape. This can beadjusted by correspondingly configuring the number of laser shots, theirenergy, their duration, and/or other parameters in terms of laserdrilling.

In an embodiment, a lateral offset between a center of the firsttapering portion and a center of the second tapering portion is not morethan 3 μm. In an ideal case (which is however difficult to manufacturefor each and every of a large plurality of through holes in a componentcarrier), there is no offset at all. In the context of the presentapplication, the term “offset” may particularly denote a spatialmismatch or lateral displacement between centers of laser beams and/orcenters of partial holes in the electrically insulating layer structureformed by a laser beam on the front side and on the back side of theelectrically insulating layer structure. More specifically, the term“offset” may refer to a spatial distance between the mentioned centerswhen comparing them at the front side with the back side. The presenceof such an offset may be the consequence of a process of manufacturing athrough hole in an electrically insulating layer structure. In thecontext of such a process, the electrically insulating layer structuremay firstly be made subject to a first laser processing from the frontside, then the electrically insulating layer structure may be flipped orturned around by 180°, and subsequently a second laser treatment of theelectrically insulating layer structure is accomplished from its backside. Due to a spatial mismatch with regard to a mutual alignmentbetween laser source and electrically insulating layer structure duringfront side and back side laser processing, the mentioned offset mayoccur. When measures are taken for keeping the offset low (for instanceclamping a panel or another pre-form of the component carrier duringlaser drilling from the front side and from the back side, properalignment using alignment markers, suppression of warpage of a panel oranother pre-form of the component carrier), this low offset value alsoresults in a high reliability of the obtained component carrier.

In an embodiment, the electrically conductive bridge structure isde-limited by a first demarcation surface facing towards the first mainsurface and by a second demarcation surface facing towards the secondmain surface, wherein a distance between, on the one hand, a point onthe side wall at which a width of the through hole is minimum, and, onthe other hand, a lowermost point of the first demarcation surfaceand/or an uppermost point of the second demarcation surface is at least20 μm. If this highly advantageous design rule is respected according toa preferred embodiment of the invention, a void-free and crack-freecopper filled laser via can be obtained, since it ensures goodproperties of the copper filling at the critical position of the bridgestructure at the bottleneck of the through hole. Descriptively speaking,a sufficient amount of electrically conductive material in the mentionedregion is advantageous for ensuring reliability.

In an embodiment, the electrically conductive bridge structure isde-limited by the first demarcation surface facing towards the firstmain surface and by the second demarcation surface facing towards thesecond main surface. A central bridge plane may be defined to extendparallel to the first main surface and the second main surface andthrough a vertical center between a lowermost point of the firstdemarcation surface and an uppermost point of the second demarcationsurface. A first intersection point may be defined as a firstintersection between the central bridge plane and one of the sidewallsof the electrically insulating layer structure. Advantageously, a lengthof a shortest distance (in particular of a first perpendicular) from thefirst intersection point to the first demarcation surface may be atleast 20 μm. In the context of the present application, the term“central bridge plane” may particularly denote a virtual plane with ahorizontal extension, i.e. parallel to the two opposing main surfaces ofthe electrically insulating layer structure, and extending at a heightlevel in the middle between a lowermost point of the first demarcationsurface and an uppermost point of the second demarcation surface. In thecontext of the present application, the central bridge plane isconsidered for defining a minimum distance rule according to anexemplary embodiment of the invention. In the context of the presentapplication, the term “intersection point” is introduced as a virtualpoint used for formulating the minimum distance design rule according toan exemplary embodiment of the invention. The respective intersectionpoint is defined as a virtual intersection between the before mentionedcentral bridge plane and one of the sidewalls of the electricallyinsulating layer structure delimiting the through hole in across-sectional view. In the context of the present application, theterm “a perpendicular” may particularly denote a straight line extendingfrom a respective intersection point up to a respective demarcationsurface and intersecting this demarcation surface so that a right angleis formed between the straight line and a tangent (in particular atangent plane) on the curved demarcation surface at a position of anintersection between the straight line and the demarcation surface. Inother words and descriptively speaking, the perpendicular may correspondto a shortest connection line between the intersection point and thedemarcation surface, and may intersect the latter at a right angle. Ithas been surprisingly found that when fulfilling the mentioned specificdesign rule for the bridge structure filling part of the through hole ofa component carrier, the electric and mechanical reliability of theobtained component carrier is high. This means that undesired phenomenasuch as cracks in the electrically conductive filling medium filling thethrough hole and/or voids remaining in an interior of the through holefilled with electrically conductive material can be reliably preventedor at least strongly suppressed when meeting this design rule. Morespecifically, the mentioned design rule relates to the fact that ashortest distance between a sidewall of the through hole at the verticallevel of a central plane of the bridge structure and a respectivedemarcation surface delimiting the bridge structure should be preferablyat least 20 μm. Although it is preferable that this design rule isfulfilled for both or all intersection points between the sidewalls andthe central plane on the one hand and both demarcation surfaces on theother hand, good results have already been obtained when fulfilling thisdesign rule already for one intersection point and one demarcationsurface.

In an embodiment, the component carrier comprises a stack of at leastone electrically insulating layer structure and at least oneelectrically conductive layer structure. For example, the componentcarrier may be a laminate of the mentioned electrically insulating layerstructure(s) and electrically conductive layer structure(s), inparticular formed by applying mechanical pressure and/or thermal energy.The mentioned stack may provide a plate-shaped component carrier capableof providing a large mounting surface for further components and beingnevertheless very thin and compact.

In an embodiment, the component carrier is shaped as a plate. Thiscontributes to the compact design, wherein the component carriernevertheless provides a large basis for mounting components thereon.Furthermore, in particular a naked die as example for an embeddedelectronic component, can be conveniently embedded, thanks to its smallthickness, into a thin plate such as a printed circuit board.

In an embodiment, the component carrier is configured as one of thegroup consisting of a printed circuit board, a substrate (in particularan IC substrate), and an interposer.

In the context of the present application, the term “printed circuitboard” (PCB) may particularly denote a plate-shaped component carrierwhich is formed by laminating several electrically conductive layerstructures with several electrically insulating layer structures, forinstance by applying pressure and/or by the supply of thermal energy. Aspreferred materials for PCB technology, the electrically conductivelayer structures are made of copper, whereas the electrically insulatinglayer structures may comprise resin and/or glass fibers, so-calledprepreg or FR4 material. The various electrically conductive layerstructures may be connected to one another in a desired way by formingthrough-holes through the laminate, for instance by laser drilling ormechanical drilling, and by filling them with electrically conductivematerial (in particular copper), thereby forming vias as through-holeconnections. Apart from one or more components which may be embedded ina printed circuit board, a printed circuit board is usually configuredfor accommodating one or more components on one or both opposingsurfaces of the plate-shaped printed circuit board. They may beconnected to the respective main surface by soldering. A dielectric partof a PCB may be composed of resin with reinforcing structures (such asglass fibers or glass spheres).

In the context of the present application, the term “substrate” mayparticularly denote a small component carrier having substantially thesame size as a component (in particular an electronic component to bemounted thereon. More specifically, a substrate can be understood as acarrier for electrical connections or electrical networks as well ascomponent carrier comparable to a printed circuit board (PCB), howeverwith a considerably higher density of laterally and/or verticallyarranged connections. Lateral connections are for example conductivepaths, whereas vertical connections may be for example drill holes.These lateral and/or vertical connections are arranged within thesubstrate and can be used to provide electrical and/or mechanicalconnections of housed components or unhoused components (such as baredies), particularly of IC chips, with a printed circuit board orintermediate printed circuit board. Thus, the term “substrate” alsoincludes “IC substrates”. A dielectric part of a substrate may becomposed of resin with reinforcing particles (such as reinforcingspheres, in particular glass spheres).

The substrate or interposer may comprise or consist of at least a layerof glass, silicon (Si) or a photo imageable or dry-etchable organicmaterial like epoxy-based build-up material (such as epoxy-basedbuild-up film) or polymer compounds like polyimide, polybenzoxazole, orbenzocyclobutene.

In an embodiment, the at least one electrically insulating layerstructure comprises at least one of the group consisting of resin (suchas reinforced or non-reinforced resins, for instance epoxy resin orbismaleimide-triazine resin, more specifically FR-4 or FR-5), cyanateester, polyphenylene derivate, glass (in particular glass fibers,glass-spheres, multi-layer glass, glass-like materials), prepregmaterial, photo imageable dielectric material, polyimide, polyamide,liquid crystal polymer (LCP), epoxy-based build-up material,polytetrafluoroethylene (Teflon®), a ceramic, and a metal oxide. Teflonis a registered trademark of the Chemours Company FC of Delaware, U.S.A.Reinforcing materials such as webs, fibers or spheres, for example madeof glass (multilayer glass) may be used as well. Although prepreg, FR4,or epoxy-based build-up film or photo imageable dielectrics are usuallypreferred, other materials may be used as well. For high frequencyapplications, high-frequency materials such as polytetrafluoroethylene,liquid crystal polymer and/or cyanate ester resins may be implemented inthe component carrier as electrically insulating layer structure.

In an embodiment, at least one of the integral electrically conductivestructure, the bridge structure, the at least one bulk structure, andone or more optional electrically conductive layer structures comprisesat least one of the group consisting of copper, aluminum, nickel,silver, gold, palladium, and tungsten. Although copper is usuallypreferred, other materials or coated versions thereof are possible aswell, in particular coated with supra-conductive material such asgraphene.

At least one component may be surface mounted on and/or embedded in thecomponent carrier and can in particular be selected from a groupconsisting of an electrically non-conductive inlay, an electricallyconductive inlay (such as a metal inlay, preferably comprising copper oraluminum), a heat transfer unit (for example a heat pipe), a lightguiding element (for example an optical waveguide or a light conductorconnection), an electronic component, or combinations thereof. Forexample, the component can be an active electronic component, a passiveelectronic component, an electronic chip, a storage device (for instancea DRAM or another data memory), a filter, an integrated circuit, asignal processing component, a power management component, anoptoelectronic interface element, a light emitting diode, aphotocoupler, a voltage converter (for example a DC/DC converter or anAC/DC converter), a cryptographic component, a transmitter and/orreceiver, an electromechanical transducer, a sensor, an actuator, amicroelectromechanical system (MEMS), a microprocessor, a capacitor, aresistor, an inductance, a battery, a switch, a camera, an antenna, alogic chip, and an energy harvesting unit. However, other components maybe embedded in the component carrier. For example, a magnetic elementcan be used as a component. Such a magnetic element may be a permanentmagnetic element (such as a ferromagnetic element, an antiferromagneticelement, a multiferroic element or a ferrimagnetic element, for instancea ferrite core) or may be a paramagnetic element. However, the componentmay also be a substrate, an interposer or a further component carrier,for example in a board-in-board configuration. The component may besurface mounted on the component carrier and/or may be embedded in aninterior thereof. Moreover, also other components, in particular thosewhich generate and emit electromagnetic radiation and/or are sensitivewith regard to electro-magnetic radiation propagating from anenvironment, may be used as component.

In an embodiment, the component carrier is a laminate-type componentcarrier. In such an embodiment, the component carrier is a compound ofmultiple layer structures which are stacked and connected together byapplying a pressing force and/or heat.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1, FIG. 2 and FIG. 3 illustrate cross-sectional views of structuresobtained during carrying out a method of manufacturing a componentcarrier with a through hole by a multiple laser shot treatment fromopposing sides and by subsequently filling the through hole withelectrically conductive filling medium according to an exemplaryembodiment of the invention.

FIG. 4 illustrates a cross-sectional view of a component carrier with ametal filled through hole and horizontal tracks according to anexemplary embodiment of the invention.

FIG. 5 illustrates a cross-sectional view of a pre-form of a componentcarrier with a through hole having two tapering sections and a straightsection in between according to another exemplary embodiment of theinvention.

FIG. 6 and FIG. 7 illustrate cross-sectional views of conventionalcomponent carriers with through hole.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

The aspects defined above and further aspects of the invention areapparent from the example of embodiments to be described hereinafter andare explained with reference to these examples of embodiments.

The illustrations in the drawings are schematically presented. Indifferent drawings, similar or identical elements are provided with thesame reference signs.

Before referring to the drawings, exemplary embodiments will bedescribed in further detail, some basic considerations will besummarized based on which exemplary embodiments of the invention havebeen developed.

According to an exemplary embodiment, one or both main surfaces of anelectrically insulating layer structure may remain exposed and uncoveredby electrically conductive layer structures at the time of forming oneor more through holes extending through the electrically insulatinglayer structure by laser drilling. Thus, a manufacturing method relatingto such an embodiment comprises forming the through hole(s) in theelectrically insulating layer structure without covering the mainsurfaces of the electrically insulating layer structure with anelectrically conductive layer structure, such as a copper foil. Inembodiment, a laser through hole may thus be formed without copper onsurfaces of a core made subject to laser drilling.

Conventionally, the starting point of manufacturing a printed circuitboard (PCB) or a substrate is a core comprising an insulating layerstructure, covered with copper layers on both surfaces. Before creationof structures and the first build-up layer, laser through holes arecreated for aligning and electrically connecting the two copper layersof the core. However, there are several drawbacks of such a conventionaltechnology:

Firstly, due to the heat of the laser beam, the resin below the coppernear to the opening is melting and thus a so-called overhang may becreated. An overhang is critical, as during the plating-process, voidscan be created which might lead to cracks.

Secondly, through holes have to be created by drilling from both sides.Due to machine tolerances, a significant shift from the two sides(front-back shift or offset) cannot be avoided.

Thirdly, especially when working with thin cores (in particular coreshaving a thickness less than 110 μm) so-called bottle holes can becreated by the laser by irradiating the copper-layer on the ground. Ifthe copper-layer is irradiated, it cannot be processed by laser from theother side anymore.

FIG. 6 shows a conventional component carrier 200 with a through hole208 suffering from a significant overhang 209 and suffering from frontto back side offset 207. Exemplarily, the overhang 209 at the upperleft-hand side of FIG. 6 is denoted with reference c. According to FIG.6, the through hole 208 is formed in a layer stack composed of a centraldielectric core 202 covered on both opposing main surfaces with arespective patterned copper foil 203, 205. Due to the excessive offset207 and the significant overhang 209, a high risk of cracks and voidsoccurs when the through hole 208 is filled with plated copper (notshown).

FIG. 7 shows another conventional component carrier 200 with a bottlehole. Reference numeral 211 illustrates laser irradiated copper. Aresulting reflection of the laser light in an upward direction increasesthe overhang 209 and results in severe reliability issues.

In contrast to the conventional approaches according to FIG. 6 and FIG.7 and according to an exemplary embodiment of the invention, a componentcarrier having a core layer comprising through holes is provided withoutsuffering from overhang and bottle holes, and which, in particular interms of thin core layers, may also prevent an excessive offset.

A corresponding manufacturing process according to an exemplaryembodiment can be as follows: a starting point may be a purelydielectric electrically insulating layer, for instance FR4, preferablywithout any metal. Laser through holes may be drilled, preferably withuniform laser energy and power to prevent glass protrusion, bottomundercut and winking (i.e. removal of resin from glass). In contrast tothis, when creating laser through holes in copper cores, laser energyand power has to be changed among the laser shots to prevent bottleholes.

When using thin core layers (in particular consisting only of dielectricmaterial), it can be possible to shoot with a laser beam from only oneside. Then, any offset can be prevented and as a consequence the densityof connections can be increased.

FIG. 1 to FIG. 3 illustrate cross-sectional views of structures obtainedduring carrying out a method of manufacturing a component carrier 100,shown in FIG. 3, with a through hole 108 by a multiple laser shottreatment from opposing sides and by subsequently filling the throughhole 108 with an electrically conductive filling medium 151 formed bymultiple filling procedures according to an exemplary embodiment of theinvention.

Referring to FIG. 1, a first part of the through hole 108 extendingbetween a first main surface 104 and a second main surface 106 of anelectrically insulating layer structure 102 is formed by carrying out afirst laser shot 115. Laser processing as described referring to FIG. 1may be carried out by an appropriate laser source, for instance by anexcimer laser and/or a carbon dioxide laser. In the illustratedembodiment, the electrically insulating layer structure 102 may compriseresin, in particular epoxy resin, optionally comprising reinforcingparticles such as glass fibers or glass particles. A vertical thicknessH of the electrically insulating layer structure 102 may for instance benot more than 110 μm, in particular in a range between 40 μm and 60 μm.

A blind hole is formed by the first laser shot 115 in the upper mainsurface 104 of the electrically insulating layer structure 102. Theblind hole later constitutes a first tapering portion 114 of the throughhole 108.

Still referring to FIG. 1, the process of forming the through hole 108is continued, after carrying out the first laser drilling from the firstmain surface 104 with one laser shot 115 as described above, by carryingout a second laser drilling from the second main surface 106 with onefurther laser shot 117, i.e. by altogether two laser shots 115, 117.Thereby, the illustrated through hole 108 is formed with first taperingportion 114 extending from the first main surface 104 and resulting fromthe first laser shot 115, and with second tapering portion 116 extendingfrom the second main surface 106 and resulting from the second lasershot 117. The second laser shot 117 is carried out after the first lasershot 115 and from the back side, i.e. extending the previously formedblind hole into the through hole 108 extending through the entirethickness of the electrically insulating layer structure 102. After thefirst laser shot 115 and before the second laser shot 117, the structureshown in FIG. 1 may be flipped or turned around by 180° so that thelaser source (not shown) may remain stationary.

According to FIG. 1, the through hole 108 is formed by irradiatingfirstly one and thereafter the other of the exposed main surfaces 104,106 of the electrically insulating layer structure 102, being notcovered by an electrically conductive layer structure, with a respectivelaser shot 115, 117. More specifically, forming the through hole 108comprises irradiating the first main surface 104, being not covered byan electrically conductive layer structure with first laser shot 115 andsubsequently irradiating the second main surface 106, being not coveredby an electrically conductive layer structure, with second laser shot117. Thus, forming the through hole 108 comprises directly irradiatingeach of the exposed main surfaces 104, 106 of the electricallyinsulating layer structure 102 with a respective one of the laser shot115, 117. The laser shots 115, 117 may provide the electricallyinsulating layer structure 102 with a uniform laser energy.

In one embodiment, the obtained through hole 108 with a substantialX-shape as shown in FIG. 1 may be made subject to a subsequent procedureof filling the through hole 108 with electrically conductive materialsuch as copper. The shape of the through hole 108 may also be denoted asthe shape of a vertical bow tie. The through hole filling proceduresillustrated and described below referring to FIG. 2 and FIG. 3 can starton the basis of through hole 108 with substantial X-shape as shown inFIG. 1. Alternatively and referring to FIG. 5, it is also possible tocarry out a further laser shot 119 before filling the through hole 108with electrically conductive material, which results in a modified shapeof through hole 108.

Again referring to FIG. 1, a narrowest diameter, C, of the through hole108 may be in a range between approximately 55 μm and approximately 70μm. The value of this parameter may be adjusted in particular bycorrespondingly adapting the laser processing described referring toFIG. 1 or FIG. 5. For instance, selection of the type of laser source,of the diameter of the respective laser beam, and/or of the temporallength of laser pulses used for laser shots 115, 117 and optionally 119are parameters having an impact on the value of the narrowest diameter,C. Furthermore, a combination with other geometrical parameters may behighly advantageous, as will be described below.

A preferably thin core layer with thickness H, in form of purelydielectric electrically insulating layer structure 102, with laserthrough hole 108 has the shape of a (preferably small) tapering outsideof the center to facilitate subsequent bridging, as shown in FIG. 3.Vertical thickness H (which may also be denoted as dielectric thickness)of the electrically insulating layer structure 102 may be not more than110 μm (for instance may be in the range between 40 μm and 60 μm), sothat the electrically insulating layer structure 102 is embodied as athin core layer. Forming a copper filled laser via in such a thin corelayer is usually highly critical. With the concept of forming throughhole 108 in a purely dielectric layer structure 102 and in particular incombination with the described set of parameters, it is however possibleto obtain a high via reliability also with such a thin core layer.

As can be taken from a detail 131 and a detail 133 in FIG. 1, aroughness Rz of sidewalls 112 in the first tapering portion 114 issmaller than a roughness Rz of sidewalls 112 in the second taperingportion 116. This corresponds to a vertical extension d1 of the firsttapering portion 114 being larger than a vertical extension d2 of thesecond tapering portion 116, i.e. d1>d2. For instance, d1 may be atleast 60% of H, whereas d2 may be not more than 40% of H, and d1+d2=H.Descriptively speaking, the smaller surface area of the sidewalls 112 inthe second tapering portion 116 providing a small adhesion surface areawith regard to subsequently applied metallic material may be compensatedby the locally increased roughness Rz in the second tapering portion116, as compared to the smaller roughness Rz in the first taperingportion 114 providing a larger adhesion surface area with regard to thesubsequently applied metallic material. Thus, sidewalls 112 may beformed with different values of the roughness Rz on the upper/lower sideof the, or in other words above and below a narrowest portion of throughhole 108. Preferably, the higher roughness is on the smaller side to thetapering in order to balance the adhesion of the copper on theside-walls 112 of later formed seed layer 144 and/or plating layer 153.The longer sidewall 112 may have a smoother surface, whereas the shortersidewall 112 may have a rougher surface. In particular and as describedbelow in further detail, the roughness Rz of sidewalls 112 in the firsttapering portion 114 and in the first tapering portion 114 may bedifferent for ensuring a homogeneous adhesion of a later formedelectrically conductive filling medium 151 on the sidewalls 112.

As yet another one of the advantageous set of parameters, a lateraloffset J (which may also be denoted as via offset between front andbottom side between a center of the first tapering portion 114 and acenter of the second tapering portion 116, as shown in FIG. 1) is notmore than 3 μm. More specifically, the lateral offset J may be definedas a horizontal distance between a vertical center axis 191 of the firsttapering portion 114 and a vertical center axis 193 of the secondtapering portion 116. Preferably, the value of the offset J is not morethan 3 μm. Highly preferably, the value of the offset J is not more than1 μm. This further reduces the risk of cracks and voids.

In order to obtain the layer structure shown in FIG. 2, the through hole108 according to FIG. 1 is made subject to a first procedure of fillingit with an electrically conductive filling medium 151 such as copper.

In order to accomplish this, it is preferable to firstly carry out anelectroless deposition procedure to thereby form a thin seed layer 144of copper directly covering the sidewalls 112 of the electricallyinsulating layer structure 102 delimiting the through hole 108. This canbe seen in a detail 121 in FIG. 4. A thickness, m, of the seed layer 144may be for instance 0.5 μm. However, it is also possible that the seedlayer 144 has a thickness above 1 μm and/or that several cumulative seedlayers are provided. For example, a thickness of a seed layer 144 or acumulative thickness of a plurality of seed layers 144 may be in a rangebetween 0.5 μm and 5 μm. When multiple seed layers 144 are provided,they may comprise an organic (for instance polymer layer, a palladiumlayer, and/or a copper layer.

Moreover, and as shown as well in detail 121, the method may optionallyfurther comprise forming a bonding layer 155 having a substantiallyhomogeneous thickness h, between the sidewalls 112 and the belowdescribed plating layer 153 (or the optional seed layer 144). Theoptional bonding layer 155 may be provided with more or less similar orhomogeneous thickness, h, on the core layer-type electrically insulatinglayer structure 102 and on the sidewalls 112 of the opening or throughhole 108 at least on one side.

Subsequently, further electrically conductive material (such as copper)may be deposited in form of plating layer 153 on the seed layer 144and/or on the bonding layer 155 by a plating procedure, in particular bygalvanically plating. Alternatively, it is also possible to omit seedlayer 144 and/or bonding layer 155 and apply the material of platinglayer 153 directly on the dielectric surface of the sidewalls 112 ofelectrically insulating layer structure 102. Thus, the sidewalls 112 aswell as the main surfaces 104, 106 may be covered by a thicker platinglayer 153 of the electrically conductive filling medium 151 such ascopper. For instance, the plating layer 153 may have a substantiallyconstant thickness, b, of for instance 10 μm.

As can be taken from a detail 171 and a detail 173 in FIG. 2, theroughness Rz of sidewalls 112 in the first tapering portion 114 issmaller than in the second tapering portion 116. As a result and asdescribed above, a homogeneously high adhesion of the plating layer 153to the sidewalls 112 over the entire extension of through hole 108 canbe ensured.

Thus, the manufacturing procedure is continued by forming part ofelectrically conductive filling medium 151 by forming plating layer 153,having a substantially homogeneous thickness b, as an integral structurecovering the sidewalls 112 of the through hole 108 and covering the mainsurfaces 104, 106. As can be taken from detail 121, formation of theplating layer 153 is carried out after formation of seed layer 144and/or after formation of bonding layer 155. The integral electricallyconductive structure or plating layer 153 covers sidewalls 112 of thethrough hole 108 and the main surfaces 104, 106 of the electricallyinsulating layer structure 102. However, no metal foil is arrangedbetween the integral electrically conductive structure 153 and the mainsurfaces 104, 106, so that no disturbing overhang is created. As shownin FIG. 2, the integral electrically conductive structure 153continuously lines the sidewalls 112 and the main surfaces 104, 106including angled transitions 139 between the sidewalls 112 and the mainsurfaces 104, 106. The integral electrically conductive structure orplating layer 153 can be arranged directly on the seed layer 144,directly on the bonding layer 155, or directly on the dielectricsidewalls 112 and the dielectric main surfaces 104, 106.

Hence, FIG. 2 shows formation of plating layer 153 as a metal layer withmore or less uniform thickness b on the purely dielectric core layer (inform of electrically insulating layer structure 102) and on thesidewalls 112 of the opening at least on one side. It is also possibleto create the first metal layer on one side of the electricallyinsulating layer structure 102 by PVD techniques like sputtering and onthe other side with electroless deposition.

Referring to FIG. 3, a further plating procedure may be carried outfollowing the one described referring to FIG. 2 so as to form anelectrically conductive bridge structure 110 with a substantiallyhorizontal portion connecting opposing sidewalls 112 of the through hole108. The bridge structure 110 also comprises slanted legs covering theplating layer 153. As shown, the electrically conductive bridgestructure 110, which also forms part of the electrically conductivefilling medium 151, is formed to be delimited by an upper firstdemarcation surface 118 oriented upwardly and by a lower seconddemarcation surface 120 orientated downwardly. Forming the electricallyconductive bridge structure 110 may be carried out by galvanic plating,preferably following the optional formation of the seed layer 144, theoptional formation of the bonding layer 155, and the formation of theplating layer 153. Thus, the bridge structure 110 forms a substantiallyhorizontal bridge between opposing sidewalls 112 of the electricallyinsulating layer structure 102 delimiting the through hole 108 andcomprises slanted legs on the plating layer 153.

In the region of the narrowest portion of the through hole 108, thesubstantially horizontal bridge structure 110 is formed connecting theopposing sidewalls 112. A concave upper limiting surface corresponds tothe first demarcation surface 118, whereas a lower concave limitingsurface of the bridge structure 110 corresponds to the seconddemarcation surface 120.

Still referring to FIG. 3, a first electrically conductive bulkstructure 148 filling a major part above the first demarcation surface118 and a second electrically conductive bulk structure 150 filling amajor part below the second demarcation surface 120 are formed. This canbe done by carrying out a further galvanic plating following theprevious plating procedure of forming the bridge structure 110.

Thus, the component carrier 100 according to FIG. 3 can be obtained bycarrying out further plating. Thereby, the bulk structures 148, 150,which may for instance consist of copper, can be obtained. In the shownembodiment, a small dip 125, 127, respectively, remains at an upper sideor a lower side of the shown component carrier 100. In otherembodiments, the bulk structures 148, 150 fill the remaining recessesabove the first demarcation surface 118 and below the second demarcationsurface 120 almost completely. It should be said that it is well-knownby a skilled person that the demarcation surfaces 118, 120 are clearlyvisible when imaging a cross-section of the component carrier 100.

In the shown embodiment, the illustrated component carrier 100 can be alaminate-type plate-shaped component carrier 100 such as a printedcircuit board (PCB). The component carrier 100 may comprise a layerstack composed of the central electrically insulating layer structure102 being covered on each of its opposing main surfaces 104, 106 by theplated electrically conductive filling medium 151. Preferably, theelectrically insulating layer structure 102 is made of a fully curedmaterial such as FR4. The electrically conductive filling medium 151 maybe plated copper.

The through hole 108 extending through the electrically insulating layerstructure 102 between the first main surface 104 and the second mainsurface 106 is filled in a central portion thereof with electricallyconductive filling medium 151 such as copper. This electricallyconductive filling medium comprises the electrically conductive bridgestructure 110 connecting opposing sidewalls 112 of the electricallyinsulating layer structure 102 delimiting the through hole 108. In theconfiguration of FIG. 3, the horizontal section of the bridge structure110 is located around a narrowest portion of the substantially X-shapedthrough hole 108. Apart from its substantially horizontal section, thebridge structure 110 also covers the sidewalls 112 and therefore has asubstantial H-shape. The electrically conductive bridge structure 110 isarranged on the plating layer 153 and connects opposing sidewalls 112 ofthe electrically insulating layer structure 102 delimiting the throughhole 108.

As mentioned above, as another advantageous design parameter, narrowesthorizontal diameter C (which may also be denoted as via middle diameterof the through hole 108) may be in a range between 55 μm and 70 μm.

As yet another one of the advantageous set of parameters, a minimumvertical thickness B (which may also be denoted as total bridging copperthickness of the bridge structure 110) is at least 20 μm. It has turnedout that a sufficiently thick bridge structures 110 has a very positiveimpact on via reliability.

Hence, FIG. 3 illustrates plating of further layers (for instance nextlayer for bridging, afterwards filling the hole) to thereby completeformation of the electrically conductive filling medium 151.

As shown in FIG. 3 and as a consequence of the described manufacturingprocess, the integral electrically conductive structure or plating layer153 connects the sidewalls 112 with the main surfaces 104, 106 withoutany overhang (compare reference numeral 209 in the conventionalstructures illustrated in FIG. 6 and FIG. 7). Furthermore, as shown inFIG. 3 as well, the integral electrically conductive structure orplating layer 153 substantially (with the only exception of the optionalseed layer 144 and/or the optional bonding layer 155) consists of platedmetal and is in particular free of laminated copper foils.

FIG. 4 illustrates a cross-sectional view of a component carrier 100with vertical through hole 108 and horizontally extending electricallyconductive tracks 181 according to an exemplary embodiment of theinvention.

During and/or after formation of the electrically conductive fillingmedium 151, the plating layer 153, the bridge structure 110 and the bulkstructures 148, 150 may be patterned on one or both of the main surfaces104, 106 so as to form one or several layer stacks 159 on one or both ofthe first main surface 104 and the second main surface 106. By takingthis measure, it is possible to form one or more electrically conductivetracks 181 in form of the stacks 159 of multiple plated structures 183to 185 on the electrically insulating layer structure 102simultaneously, i.e. in common deposition procedures, with the formationof the electrically conductive filling medium 151 in the through hole108. This is a very efficient approach of filling laser through holes108 and forming electrically conductive tracks 181 of component carrier100. In order to form the stacks 159, the method comprises formingvarious resist structures before and/or between forming differentconstituents of the electrically conductive filling medium 151.

According to FIG. 4, the electrically conductive filling medium fillsthe through hole 108 and comprises a first number of multiple stackedstructures 153, 110, 148, 150. Thus, the first number is four in thisembodiment. Moreover, electrically conductive tracks 181 partially covereach of the main surfaces 104, 106 of the electrically insulating layerstructure 102. The tracks 181 on the first main surface 104 comprise asecond number of multiple stacked structures 153, 110, 148, so that thesecond number of the tracks 181 on the first main surface 104 is threein this embodiment. Correspondingly, the tracks 181 on the second mainsurface 106 comprise a second number of multiple stacked structures 153,110, 150, so that the second number of the tracks 181 on the second mainsurface 104 is three in this embodiment. Thus, the first number is byone larger than each of the second numbers.

In another embodiment, the first number and the second number may be thesame (in particular both three).

Hence, depending on details of the described structuring method, resistmay be applied between the individual manufacturing processes. Forinstance, in terms of semi-additive processing (SAP), resist may beapplied after forming bonding layer 155 or after forming plating layer153 depending on the material of bonding layer. In a full additiveprocessing approach, such a resist may be applied after forming bondinglayer 155 to create electrically conductive paths at the time of fillingthe through holes 108. Thus, the copper structure (in particular interms of the number of layers and/or height of the first metal layer) ofthe tracks 181 may be similar to those on the sidewalls 112 of the laserthrough hole 108, as shown in FIG. 4.

Still referring to FIG. 4, a distance, f, between a point 188 on thesidewall 112 at which a width of the through hole 108 is minimum, and alowermost point 186 of the first demarcation surface 118 is at least 20μm. If this highly advantageous design rule is respected according to apreferred embodiment of the invention, a void-free and crack-free copperfilled laser via can be obtained. Correspondingly, a distance, g,between another point 190 (opposing point 188) on the sidewall 112 atwhich the width of the through hole 108 is minimum, and the lowermostpoint 186 of the first demarcation surface 118 is at least 20 μm. It isalso advantageous if a distance, k, between the point 188 and anuppermost point 192 of the second demarcation surface 120 is at least 20μm. Correspondingly, a distance, n, between the point 190 and theuppermost point 192 of the second demarcation surface 120 may be atleast 20 μm. These design rules also contribute to a high reliability ofcomponent carrier 100.

In a conventional approach, copper layers of the core have to be etchedafter plating the holes in order to create the structure which causes alot of copper waste. In contrast to this, exemplary embodiments of theinvention (such as the one shown in FIG. 4) reduce the ecological footprint of a PCB perceptible.

Still referring to FIG. 4, at least part of the stacks 159 as well asportions of the electrically conductive filling medium 151 filling thethrough hole 108 and extending beyond the main surfaces 104, 106 may beformed by semi-additive processing. The laterally delimited layer stacks159 and upwardly and downwardly protruding portions of the electricallyconductive filling medium 151 (composed of the plating layer 153, thebridge structure 110 and a respective one of the bulk structures 148,150) have sidewalls having an angle, β, with a respective one of thefirst main surface 104 or the second main surface 106 very close to 90°.For instance, the angle β may be in a range between 85° and 95°, andpreferably in a range between 89° and 91°.

FIG. 5 illustrates a cross-sectional view of a pre-form of a componentcarrier 100 with a through hole 108 according to still another exemplaryembodiment of the invention.

Referring to the embodiment of FIG. 5, forming the through hole 108comprises carrying out, in addition to the first laser drilling from thefirst main surface 104 with one laser shot 115 and in addition to thesecond laser drilling from the second main surface 106 with the secondlaser shot 117, a third laser drilling by a third laser shot 119 fromthe backside as well. FIG. 5 hence shows how a third laser shot 119 iscarried out from the back side or from the second main surface 106 ofthe electrically insulating layer structure 102 following the proceduredescribed referring to FIG. 1. By taking this measure, the shape of thethrough hole 108 can be further manipulated so that the narrowestportion of the through hole 108 is spatially widened and a for instancesubstantially circular cylindrical central connection portion 134 isformed between the tapering portions 114, 116. According to FIG. 5, twoopposing exterior portions of the through hole 108 are tapering, whereasa central portion of the through hole 108 is substantially cylindrical.In the configuration of FIG. 5, the central connection portion 134connects the first tapering portion 114 with the second tapering portion116.

The horizontal section of the bridge structure 110 may be located in thecentral connection portion 134 according to FIG. 5. Some or all of thedesign rules concerning the various dimensions explained above may alsobe fulfilled in the embodiment according to FIG. 5, but will not beexplained again for the sake of conciseness.

It should be noted that the term “comprising” does not exclude otherelements or steps and the “a” or “an” does not exclude a plurality.Also, elements described in association with different embodiments maybe combined.

Implementation of the invention is not limited to the preferredembodiments shown in the figures and described above. Instead, amultiplicity of variants is possible which use the solutions shown andthe principle according to the invention even in the case offundamentally different embodiments.

The invention claimed is:
 1. A method of manufacturing a componentcarrier, wherein the method comprises: forming a through hole between afirst main surface and a second main surface of an electricallyinsulating layer structure by removing material from at least the firstmain surface of the electrically insulating layer structure, inparticular by irradiating at least the first main surface of theelectrically insulating layer structure with at least one laser shot,wherein the first main surface from which material is removed, inparticular which is to be irradiated, is not covered by an electricallyconductive layer structure at least in a surface region in which thethrough hole is to be formed; subsequently at least partially coveringsidewalls delimiting the through hole and at least partially coveringthe first main surface of the electrically insulating layer structure byan electrically conductive medium to form an integral electricallyconductive structure; wherein the integral electrically conductivestructure is formed by at least two galvanic plating processes to haveat least an electrically conductive bridge structure having asubstantially horizontal portion connecting the opposing sidewalls ofthe through hole and a first electrically conductive bulk structure onthe electrically conductive bridge structure, wherein a distance betweena point on the sidewall, at which a width of the through hole isminimum, and a lowermost point of the first electrically conductive bulkstructure is at least 20 μm.
 2. The method of manufacturing a componentcarrier according to claim 1, comprising at least one of the followingfeatures: no electrically conductive layer structure, in particular nocopper foil, is arranged between the integral electrically conductivestructure and the first main surface; the integral electricallyconductive structure is arranged on a seed layer; a total thickness ofat least two galvanically plated metal layers of the integralelectrically conductive structure is substantially homogenous in atleast a part of the through hole and in at least a part of the firstmain surface; wherein a portion of a galvanically plated metal layer inthe through hole, which includes the bridge structure, has a thicknesswhich increases in a direction from the first main surface towards thesecond main surface to a value smaller than a narrowest horizontaldiameter of the through hole so that the substantially horizontalportion has a concave first demarcation surface.
 3. The method ofmanufacturing a component carrier according to claim 1, wherein themethod comprises: providing the electrically insulating layer structurewith a thickness of less than 110 μm; wherein the through hole is formedwith: a first partial hole extending from the first main surface intothe electrically insulating layer structure; a second partial holeextending from the second main surface into the electrically insulatinglayer structure; and a lateral offset between a center axis of the firstpartial hole and a center axis of the second partial hole being lessthan 3 μm, in particular less than 1 μm.
 4. The method of manufacturinga component carrier according to claim 1, comprising at least one of thefollowing features: forming at least one electrically conductive trackpartially covering at least one of the main surfaces of the electricallyinsulating layer structure and comprising a second number of multiplestacked structures; wherein a difference between the first number andthe second number is zero or one, wherein in particular the first numberis three or four and/or the second number is three; wherein forming thethrough hole comprises irradiating the first main surface, without beingcovered by an electrically conductive layer structure, with a firstlaser shot and subsequently irradiating the second main surface, withoutbeing covered by an electrically conductive layer structure, with onlyone second laser shot; wherein forming the through hole comprisesirradiating the first main surface, without being covered by anelectrically conductive layer structure, with a first laser shot andirradiating the second main surface, without being covered by anelectrically conductive layer structure, with two second laser shots;wherein forming the through hole comprises irradiating the electricallyinsulating layer structure, without at least the first main surfacebeing covered by an electrically conductive layer structure, only fromthe first main surface, not from the second main surface; wherein thefirst main surface to be irradiated is not covered at all by anelectrically conductive layer structure during the irradiating; whereinthe first main surface to be irradiated is, during the irradiating,covered only partially by an electrically conductive layer structure ina surface region of the first main surface which surface region is notto be irradiated by the at least one laser shot; wherein the methodcomprises, before the irradiating, forming an electrically conductivelayer structure on the first main surface to be irradiated, andsubsequently and still before the irradiating, removing part of theelectrically conductive layer structure at least in a surface portion ofthe first main surface which is to be irradiated by the at least onelaser shot; wherein forming the through hole comprises directlyirradiating the exposed first main surface of the electricallyinsulating layer structure with the at least one laser shot; whereinforming the through hole, in particular by laser shots irradiated ontothe electrically insulating layer structure from both opposing mainsurfaces, is carried out with a uniform laser energy; wherein the methodcomprises forming at least one electrically conductive track comprisinga stack of multiple plated structures on the electrically insulatinglayer structure at least partially simultaneously with the formation ofthe electrically conductive medium and/or by semi-additive processing.5. The method according to claim 1, wherein the method comprises formingat least part of the integral electrically conductive structure with anannular shape and/or a substantially homogeneous thickness, inparticular following formation of a seed layer.
 6. The method accordingto claim 5, comprising at least one of the following features: whereinthe method comprises forming, by plating, part of the electricallyconductive medium as the electrically conductive bridge structure on theplating layer and connecting opposing sidewalls of the electricallyinsulating layer structure delimiting the through hole, wherein inparticular the method comprises forming part of the electricallyconductive medium by forming the first electrically conductive bulkstructure filling at least part of a volume between a first demarcationsurface, delimiting the bridge structure upwardly, and the first mainsurface and/or by forming a second electrically conductive bulkstructure filling at least part of a volume between a second demarcationsurface, delimiting the bridge structure downwardly, and the second mainsurface, wherein more particularly the method comprises forming at leastone of the group consisting of the first electrically conductive bulkstructure and the second electrically conductive bulk structure by atleast one further plating procedure; wherein the method comprisesforming a bonding layer, in particular having a substantiallyhomogeneous thickness, between at least part of the sidewalls and atleast part of the main surfaces, on the one hand, and the plating layeron the other hand.
 7. A component carrier, wherein the component carriercomprises: an electrically insulating layer structure having a firstmain surface and a second main surface; a through hole extending throughthe electrically insulating layer structure between the first mainsurface and the second main surface; an integral electrically conductivestructure covering sidewalls of the through hole, extending up to one orboth of the main surfaces and covering at least part of at least one ofthe main surfaces of the electrically insulating layer structure;wherein the integral electrically conductive structure comprises atleast two galvanically plated layers which form an electricallyconductive bridge structure having a substantially horizontal portionconnecting the opposing sidewalls of the through hole and a firstelectrically conductive bulk structure on the electrically conductivebridge structure, wherein a distance between a point on the sidewall, atwhich a width of the through hole is minimum, and a lowermost point ofthe first electrically conductive bulk structure is at least 20 μm. 8.The component carrier according to claim 7, wherein the electricallyinsulating layer structure has a thickness of less than 110 μm; and thethrough hole has: a first partial hole extending from the first mainsurface into the electrically insulating layer structure; and a secondpartial hole extending from the second main surface into theelectrically insulating layer structure; wherein a lateral offsetbetween a center axis of the first partial hole and a center axis of thesecond partial hole is less than 3 μm, in particular is less than 1 μm.9. The component carrier according to claim 7, wherein the componentcarrier comprises: at least one electrically conductive track partiallycovering at least one of the main surfaces of the electricallyinsulating layer structure and comprising a second number of multiplestacked structures; wherein a difference between the first number andthe second number is zero or one, wherein in particular the first numberis three or four and/or the second number is three.
 10. The componentcarrier according to claim 7, comprising at least one of the followingfeatures: a total thickness of at least two galvanically plated metallayers of the integral electrically conductive structure issubstantially homogenous in at least a part of the through hole and inat least a part of the at least one main surface; the integralelectrically conductive structure has an annular shape and/or asubstantially homogeneous thickness; the integral electricallyconductive structure is arranged on a seed layer; the electricallyconductive bridge structure is substantially H-shaped, wherein moreparticularly a minimum vertical thickness of the bridge structure is atleast 20 μm, in particular at least 25 μm; the component carriercomprises the first electrically conductive bulk structure filling atleast part between a first demarcation surface, delimiting the bridgestructure upwardly, and the first main surface; the component carriercomprising a second electrically conductive bulk structure filling atleast part between a second demarcation surface, delimiting the bridgestructure downwardly, and the second main surface; a portion of agalvanically plated metal layer in the through hole, which includes thebridge structure, has a thickness which increases in a direction fromthe first main surface towards the second main surface to a valuesmaller than a narrowest horizontal diameter of the through hole so thatthe substantially horizontal portion has a concave first demarcationsurface.
 11. The component carrier according to claim 10, comprising atleast one of the following features: wherein at least one of the groupconsisting of the first electrically conductive bulk structure and thesecond electrically conductive bulk structure is configured as at leastone further plating structure, in particular a plurality of stackedplating structures; wherein the plating layer, the bridge structure andthe at least one bulk structure are patterned on at least one of thefirst main surface and the second main surface so as to form at leastone laterally delimited further layer stack, wherein in particular theat least one laterally delimited further layer stack and/or a portion ofthe plating layer, the bridge structure and the at least one bulkstructure extending vertically beyond the through hole have sidewallshaving an angle with a respective one of the first main surface or thesecond main surface in a range between 85° and 95°, more particularly ina range between 89° and 91°.
 12. The component carrier according toclaim 7, comprising at least one of the following features: noelectrically conductive layer structure, in particular no copper foil,is arranged between the integral electrically conductive structure andthe at least one of the main surfaces; wherein the integral electricallyconductive structure continuously lines the sidewalls and the mainsurfaces, in particular including an angled transition between thesidewalls and the main surfaces; comprising at least one bonding layer,in particular having a substantially homogeneous thickness, between atleast part of the sidewalls and at least a part of at least one of themain surfaces, on the one hand, and the integral electrically conductivestructure on the other hand.
 13. The component carrier according toclaim 7, wherein the through hole has a first tapering portion extendingfrom the first main surface and a second tapering portion extending fromthe second main surface.
 14. The component carrier according to claim13, comprising at least one of the following features: wherein aroughness Rz of at least part of the sidewalls in the first taperingportion is different from a roughness Rz of at least part of thesidewalls in the second tapering portion; wherein a roughness Rz of atleast part of the sidewalls in the first tapering portion is smallerthan a roughness Rz of at least part of the sidewalls in the secondtapering portion, and a vertical extension of the first tapering portionlarger than a vertical extension of the second tapering portion.
 15. Thecomponent carrier according to claim 7, comprising at least one of thefollowing features: wherein a thickness of the electrically insulatinglayer structure is not more than 110 μm, in particular not more than 60μm; wherein the electrically insulating layer structure is a core layer,in particular a fully cured prepreg layer consisting of dielectricmaterial; wherein at least a part of the through hole is substantiallyX-shaped; wherein at least a part of the through hole has a central, inparticular substantially cylindrical, section between two opposingtapering sections.
 16. The component carrier according to claim 7,wherein the through hole has a continuously tapering shape or has asubstantially straight shape.
 17. The component carrier according toclaim 7, wherein the integral electrically conductive structure connectsthe sidewalls with the at least one of the main surfaces withoutoverhang.
 18. The component carrier according to claim 7, wherein theintegral electrically conductive structure exclusively consists ofplated metal, and in particular is free of laminated metal foils. 19.The component carrier according to claim 7, wherein the integralelectrically conductive structure extends continuously along one or bothof the main surfaces.
 20. The component carrier according to claim 7,further comprising at least one of the following features: at least onecomponent being surface mounted on and/or embedded in the componentcarrier, wherein the at least one component is in particular selectedfrom a group consisting of an electronic component, an electricallynon-conductive and/or electrically conductive inlay, a heat transferunit, a light guiding element, an energy harvesting unit, an activeelectronic component, a passive electronic component, an electronicchip, a storage device, a filter, an integrated circuit, a signalprocessing component, a power management component, an optoelectronicinterface element, a voltage converter, a cryptographic component, atransmitter and/or receiver, an electromechanical transducer, anactuator, a microelectromechanical system, a microprocessor, acapacitor, a resistor, an inductance, an accumulator, a switch, acamera, an antenna, a magnetic element, a further component carrier, anda logic chip; wherein at least one of the integral electricallyconductive structure, the bridge structure, and the at least one bulkstructure comprises at least one of the group consisting of copper,aluminum, nickel, silver, gold, palladium, and tungsten, any of thementioned materials being optionally coated with supra-conductivematerial such as graphene; wherein the electrically insulating layerstructure comprises at least one of the group consisting of resin, inparticular reinforced or non-reinforced resin, for instance epoxy resinor Bismaleimide-Triazine resin, FR-4, FR-5, cyanate ester, polyphenylenederivate, glass, prepreg material, polyimide, polyamide, liquid crystalpolymer, epoxy-based build-up material, polytetrafluoroethylene, aceramic, and a metal oxide; wherein the component carrier is shaped as aplate; wherein the component carrier is configured as one of the groupconsisting of a printed circuit board, and a substrate; wherein thecomponent carrier is configured as a laminate-type component carrier.